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MongoDB帮助信息：db方法，collection方法

发表于：2026-11-01 作者：千家信息网编辑

千家信息网最后更新 2026年11月01日，mongos> db.help()DB methods:db.addUser(username, password[, readOnly=false])db.adminCommand(nameOrDo

千家信息网最后更新 2026年11月01日MongoDB帮助信息：db方法，collection方法

mongos> db.help()
DB methods:
db.addUser(username, password[, readOnly=false])
db.adminCommand(nameOrDocument) - switches to 'admin' db, and runs command [ just calls db.runCommand(...) ]
db.auth(username, password)
db.cloneDatabase(fromhost)
db.commandHelp(name) returns the help for the command
db.copyDatabase(fromdb, todb, fromhost)
db.createCollection(name, { size : ..., capped : ..., max : ... } )
db.currentOp() displays currently executing operations in the db
db.dropDatabase()
db.eval(func, args) run code server-side
db.fsyncLock() flush data to disk and lock server for backups
db.fsyncUnlock() unlocks server following a db.fsyncLock()
db.getCollection(cname) same as db['cname'] or db.cname
db.getCollectionNames()
db.getLastError() - just returns the err msg string
db.getLastErrorObj() - return full status object
db.getMongo() get the server connection object
db.getMongo().setSlaveOk() allow queries on a replication slave server
db.getName()
db.getPrevError()
db.getProfilingLevel() - deprecated
db.getProfilingStatus() - returns if profiling is on and slow threshold
db.getReplicationInfo()
db.getSiblingDB(name) get the db at the same server as this one
db.hostInfo() get details about the server's host
db.isMaster() check replica primary status
db.killOp(opid) kills the current operation in the db
db.listCommands() lists all the db commands
db.loadServerScripts() loads all the scripts in db.system.js
db.logout()
db.printCollectionStats()
db.printReplicationInfo()
db.printShardingStatus()
db.printSlaveReplicationInfo()
db.removeUser(username)
db.repairDatabase()
db.resetError()
db.runCommand(cmdObj) run a database command. if cmdObj is a string, turns it into { cmdObj : 1 }
db.serverStatus()
db.setProfilingLevel(level,) 0=off 1=slow 2=all
db.setVerboseShell(flag) display extra information in shell output
db.shutdownServer()
db.stats()
db.version() current version of the server
mongos>

mongos> db.myCollection.help()
DBCollection help
db.myCollection.find().help() - show DBCursor help
db.myCollection.count()
db.myCollection.copyTo(newColl) - duplicates collection by copying all documents to newColl; no indexes are copied.
db.myCollection.convertToCapped(maxBytes) - calls {convertToCapped:'myCollection', size:maxBytes}} command
db.myCollection.dataSize()
db.myCollection.distinct( key ) - e.g. db.myCollection.distinct( 'x' )
db.myCollection.drop() drop the collection
db.myCollection.dropIndex(index) - e.g. db.myCollection.dropIndex( "indexName" ) or db.myCollection.dropIndex( { "indexKey" : 1 } )
db.myCollection.dropIndexes()
db.myCollection.ensureIndex(keypattern[,options]) - options is an object with these possible fields: name, unique, dropDups
db.myCollection.reIndex()
db.myCollection.find([query],[fields]) - query is an optional query filter. fields is optional set of fields to return. e.g. db.myCollection.find( {x:77} , {name:1, x:1} )
db.myCollection.find(...).count()
db.myCollection.find(...).limit(n)
db.myCollection.find(...).skip(n)
db.myCollection.find(...).sort(...)
db.myCollection.findOne([query])
db.myCollection.findAndModify( { update : ... , remove : bool [, query:{}, sort: {}, 'new': false] } )
db.myCollection.getDB() get DB object associated with collection
db.myCollection.getIndexes()
db.myCollection.group( { key : ..., initial: ..., reduce : ...[, cond: ...] } )
db.myCollection.insert(obj)
db.myCollection.mapReduce( mapFunction , reduceFunction , )
db.myCollection.remove(query)
db.myCollection.renameCollection( newName , ) renames the collection.
db.myCollection.runCommand( name , ) runs a db command with the given name where the first param is the collection name
db.myCollection.save(obj)
db.myCollection.stats()
db.myCollection.storageSize() - includes free space allocated to this collection
db.myCollection.totalIndexSize() - size in bytes of all the indexes
db.myCollection.totalSize() - storage allocated for all data and indexes
db.myCollection.update(query, object[, upsert_bool, multi_bool]) - instead of two flags, you can pass an object with fields: upsert, multi
db.myCollection.validate( ) - SLOW
db.myCollection.getShardVersion() - only for use with sharding
db.myCollection.getShardDistribution() - prints statistics about data distribution in the cluster
db.myCollection.getSplitKeysForChunks( ) - calculates split points over all chunks and returns splitter function